Protective device for film projecting apparatus



L. OHR

Jan. 5, 1932.

PROTECTIVHDEVICE FOR FILM PROJECTING APPARATUS Filed July 14, 1930Patented Jan. 5, 1932 I UNITED STAT-Es a PAT NT OFFICE mnwm can. orwonms, GERMANY a PROTECTIVE DEVICE ronrrmr-rnornc'rmo arrana'rnsApplication filed idly 14,1930j8ei-ia1 No. 467,712, and in GermanyFebruary 21,1929.

My invention relates to a novel and simple protective device, by meansof which-film strips are prevented from "becoming ignited. when tearingordwelling withinthe path of the light rays a longer time thanadmissible. Besides securing this general object, there 1s 7 a highlyimportant object of my invention to obtain a steadya-nd continuousmovement of the film band free from vibrations, thus the result of myinventionextendingon two different directions of high importance.Hitherto, one has well been successful when using centrifugal devices,which my invention, too, employs, in operating reasonably the safetyflaps, closing the image-window of the apparatus, but nobody has beensuccessful in getting a steady, continuous run of the film band. Whenusing such safety means, this is due to the discontinuous motion of thefilm itself, which is used, by meansof a governing member viz. a rollerand-transmitting ele ments, to operate the centrifugal device thesemeans undergoing to the action of inertia transmit inversely theirdiscontinuousmove-- ment to the film band and cause it to run in a'vibrating manner. 7

My invention, therefore, consists in such a combination of the knowncentrifugal device with other elements in a distinct arrangement thatthe drawbacks above mentioned are removed.

To make my invention more clear and to give full, easy understanding ofit, drawings are annexed, in which Fig. 1 is a back elevation of thenecessary parts of'the projecting apparatus in connection with the newdriving means for the safety contrivance, Fig. i

2 a corresponding side View, Fig. 3 the same view dispensable detailsbeing omitted, F ig.

asthe centrifugal ringfrotates rapidly. I

r on the frame 7 a bracket 'm'is fixed on which N the centrifugaldevice, the means for governing the door and the gear for the former aremounted. At the top end of the bracket m, by means of eyes at, therotating shaft i to the shaft p. Furthermore, with the teeth a of'theroller a guiding roller b cooperates in the usual manner tightenedby aflat spring b By the eyes m? at one end of the bracket the centrifugaldevice is mounted, which consists of a swinging ring 9 pivotally'carried'by means of pointed pivots from a shaft f. The centrifugal ring g'is,by means of a slight ringmember h fastened to a governing sleeve h,sliding along the shaft f and governing a slight transmission lever 2',pivotally arranged at i on the wall w and connected at i to the safetydoor 70. 1

To transmit the rotation of the-governing roller (1 to the centrifugalshaft 7 two ear wheels are provided for, a small one Xed on the shaft fand a large one 03 attached to a bearing disk d freely mounted with itshub d on the governing shaft 2 and also fixed to the latter by means ofa helical spring 8.

The action is asfollows. In its normal run the film operates the roller(1, but not in a rigid manner, as hitherto, but in an elastic way, thusall shocks otherwise transmitted to the roller and inversely by thelatter again to the film band, are received and neutrailized by theconnecting spring Z. This neutralization is increased by the additionalspring 8, taking along the intermediate disk d thus rapid rotation ofthe gear wheels 11, e and further of the centrifugal shaft f areobtained; Accordingly the swinging ring 9 puts in uprightposition andthe governinglsleeve h is drawn' to the leftha-nd side,

see arrow at, Fig. 5. Due to this, the lever opensthewfindow handholdsit open. The film strip preserving a perfectly continuousmotionythe safety flap 7c rests open as lon however, the runof thefilm-and according rill ly the rotative motion of the roller (1 aredisturbed the centrifugal power ceases to act upon the ring 9 and bygravity the door is closed immediately.

I wish to be understood that my invention is not exhausted by thespecial construction and arrangement as illustrated, but it comprises ingeneral the technical idea of inserting one or several elastic means forcoupling the governing roller a or some equivalent member andtransmitting the gear for the centrifugal device, to secure by this waythe steady and continuous projecting of the film.

WVhat I claim is:

1. A protective device for film projecting apparatus, comprising incombination with a protective door, a swinging ring and a rota* ableshaft, a hollow roller operated by the film, a gearing shaft, a helicalspring, mounted within the hollow roller resiliently connecting thegearing shaft with the hollow roller, transmitting means operated by thegearing shaft and turning the rotatable shaft, a transmitting memberconnected with the swinging ring and freely sliding on the rotatableshaft, a lever operated on its one end by the transmitting member andacting on the other end upon the protective door.

2. A protective device for film projecting apparatus, comprising incombination with a protective door, a swinging ring and a rotatableshaft, a hollow roller and a counter roller resiliently mounted, thefilm passing through between them, a gearing shaft, a helical springmounted within said hollow roller and attached on its one end with itand its other end with the gearing shaft, a bearing disk freely mountedon the gearing shaft, a connecting spring joining the bearing disk tothe gearing shaft, a toothed wheel fixed to the bearing disk, a toothedwheel fixed to the rotatable shaft, a coupling sleeve slidably mountedon the rotatable shaft and attached to the swinging ring, a leverarrangement on the one hand attached to the coupling sleeve and on theother hand to the protective door.

3. A protective device for film projecting apparatus, comprising incombination with a protective door and a centrifugal device, a rollerand a counter roller both operated by the film, a gearing shaft,resilient means connecting the gearing shaft to the roller, transmittingmeans including a resilient connection for transmitting the mo tion ofthe gearing shaft to the centrifugal device, a lever arrangement forgoverning the protective door and means for transmitting the motion ofthe centrifugal device to said lever arrangement.

at. A protective means for film projecting apparatus, comprising incombination a door, a roller over which the film passes, a shaft onwhich the roller is mounted, a second shaft, a centrifugal devicemounted on the second mentioned shaft, gearing between the two shafts, aresilient connection between the first mentioned shaft and the roller,and a lever between the centrifugal device and the door, whereby whenthe centrifugal device is operated, the door will be opened.

5. A protective means for film projecting apparatus, comprising incomblnation a door, a shaft, a ring-like element mounted to tilt on theshaft, a sliding collar on the shaft, a flexible connection between thecollar and ring, a roller over which the film passes, gearing betweenthe roller and shaft, and a connection between the collar and door,whereby upon rotation of the roller the ring is tilted by centrifugalforce and the door is opened.

6. A protective means for film projecting apparatus, comprising incombination a door, a shaft, a roller mounted on the shaft, a re silientconnection between the shaft and roller, a second shaft parallel withthe first mentioned shaft, a centrifugal device mounted on the secondmentioned shaft, gearing between the two shafts, a resilient connectionbetween the gearing and. the first mentioned shaft, and a connectionbetween the centrif ug'al device and the door.

7. A protective means for film projecting apparatus, comprising a door,a shaft, a tiltable ring mounted on the shaft, a second shaft, a hollowroller mounted on the second mentioned shaft, a spring mounted in thehollow roller and connecting the latter with the shaft, means fortransmitting motion from the second mentioned to the first mentionedshaft, a sliding element mounted on the mentioned shaft and flexiblyconnected to the tiltable ring, and a pivotal connection between thedoor and the sliding element.

In testimony whereof I ailix my signature.

LUD'WIG OHR.

